Spectra and Distribution Functions of Stably Stratified Turbulence
We examine homogeneous stably stratified turbulence both freely decaying and randomly forced cases. Our principal focus is the scale size distribution of the eddies and waves (spectra) comprising the flow. We also present results for the rate of decay for unforced flows. The tools used in both spectral and decay studies are direct numerical simulations (DNS), combined with elements of the statistical theory of turbulence. For situationally maintained flows, our results are consistent with spectra that are steeper than Kolmogorov at large scales but fair over into the normal isotropic inertial range at smaller scales. The DNS decay rate of freely decaying strongly stratified turbulence is consistent with t −1. For stratified flow, our simulations are consistent with a near equilibration between waves and vortical eddies.
KeywordsDirect Numerical Simulation Isotropic Turbulence Vortex Tube Inverse Cascade Vortex Patch
Unable to display preview. Download preview PDF.
- Riley, J.J., Metcalfe, R.W., Weissman, M.A.: Direct numerical simulations of homogeneous turbulence in density stratified fluids. Proc. AIP Conf. on Nonlinear Properties of Internal Waves, (ed. Bruce J. West), 79–112 (1982) Google Scholar
- Rotta, J.: Statistische Theorie nichthomogener Turbulenz. Z. Phys. 129, 127–147 (1951) Google Scholar
- Herring, J.R., Kimura, Y., James, R., Davidson, P., Clyne, J.: Statistical and Dynamical Questions in Stratified Turbulence, in Mathematical and Physical Theory of Turbulence, Proceedings of the 2002 International Turbulence Workshop, J. Cannon and B. Shivamoggi Eds., Chapman & Hall/CRC, Taylor & Francis Group, Boca Raton London New York (2006) Google Scholar
- Fincham, A.M., Maxworthy, T., Spedding, G.R.: The horizontal and vertical structure of the vorticity field in freely-decaying, stratified grid–turbulence. Preprints, 4 th Symposium on Stratified Flows Vol. 2, Sec. A4 (1994) Google Scholar
- Kimura, Y., Herring, J.R.: Energy spectra of stably stratified turbulence. Preprint, to be submitted to J. Fluid Mech. (2010) Google Scholar
- Sukoriansky, S., Galperin, B.: Nonlinear Processes in Geophysics. Proc. London Math. Soc. 20, 10–25 (2006) Google Scholar